Do Iron Supplements Always Change Bowel Movements?

Iron requirements increase during pregnancy.

Taking iron supplements may benefit you, especially if you have -- or are at risk of developing -- iron-deficiency anemia. However, you may experience some unpleasant side effects while taking iron supplements. Although iron can affect bowel movements, taking iron supplements doesn’t necessarily mean you’ll have a change in your bowel movements.

Bowel Movement Changes

Although changes in bowel movements don’t always occur when taking iron supplements, diarrhea, constipation and black stools are very common side effects, notes MedlinePlus. You may experience one or all of these bowel changes once you start taking iron supplements -- especially if you’re taking large doses. However, individuals who take smaller doses of iron supplements, or those who ingest multivitamins containing iron, may not experience any bowel changes.

Reducing Constipation and Diarrhea

Fortunately, there are a few ways to help relieve constipation and diarrhea caused by taking iron supplements. If you’re experiencing constipation from iron supplements, a stool softener often helps correct the problem. Talk with your doctor to see which type of stool softener you should take for relief. Boosting your fiber and probiotic intake may help reduce or eliminate diarrhea. Probiotics are abundant in yogurt and kefir and are available in supplement form. Fiber-rich foods include whole grains, legumes, fruits, vegetables, nuts, seeds and fiber-fortified foods.

Iron Toxicity Concerns

Although some changes in bowel movements are common and expected when taking iron supplements, certain changes in your stool are cause for concern. The University of Maryland Medical Center reports that ingesting too much iron from supplements can cause bloody diarrhea, vomiting and even death. Therefore, even if you have iron-deficiency anemia, take only the dose of iron recommended by your health care provider, and see you doctor immediately if you’re experiencing bloody stools.

Dietary Sources of Iron

Many adults can get all the dietary iron they need by eating a well-balanced diet containing iron-rich foods. Getting your iron from foods instead of supplements may help you avoid unpleasant bowel changes. Try iron-rich lean meats, poultry, seafood, legumes, tofu, spinach and iron-fortified breakfast cereals to help meet your daily iron needs. Heme iron, the type found in animal foods, is absorbed more easily by the body than non-heme iron, the type found in plant foods. Consume foods that contain heme iron along with non-heme iron-containing foods to increase their absorption in your body. Vitamin C also enhances non-heme iron absorption when consumed at the same time.

About the Author

Erin Coleman is a registered and licensed dietitian. She also holds a Bachelor of Science in dietetics and has extensive experience working as a health writer and health educator. Her articles are published on various health, nutrition and fitness websites.